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New study casts shadow over efficacy of mammograms to save lives

February 17th 2014 / Hanna Ibraheem


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A new study has raised questions over the effectiveness of mammograms in detecting cancer, writes Hanna Ibraheem

In 2011, 11,684 women died from breast cancer in the UK. This number is generally falling, thanks to better awareness and treatments; in order to detect the disease early, women are usually advised to have a mammogram – an X-ray of the breast. However, a recent study has revealed that being screened may make no difference to the mortality rate, casting a tidal wave of fear and confusion across women and doctors.

The research, published in the British Medical Journal, collated data from 89,835 women in Canada, aged 40 to 59. It spans over a quarter of a century, making it one of the biggest studies in mammography ever conducted and therefore pretty significant. Participants were randomly assigned to have mammograms with physical breast exams, while the rest were allocated to have only the physical exams, the aim being to work out whether there were fewer deaths if detected by a mammogram. Shockingly, the findings suggested that the death rate of those who had mammograms was the same as those who did not.

Supporters of the test often state that women whose breast cancer is diagnosed by mammogram live longer than those whose cancer is identified by a physical examination. While the study confirmed this, the researchers concluded that its advantage was deceptive. They wrote that if the cancer rejects treatment, it would be fatal no matter when it is detected. Additionally, finding it by physical examination years after a woman could have had a mammogram meant that she lived longer knowing she had cancer, not that she lived longer overall.

The study also proposed that the use of mammograms led to “over-diagnosis”. Over 22 per cent of cancer cases discovered by screening was actually harmless. One in five cancers found with the X-ray were treated but did not pose an actual threat to the women’s health, and therefore didn’t need to be treated at all; this represented one out of 424 women, who might go on to have treatment such as chemotherapy and surgery unnecessarily. But doctors make that choice because there’s no way of knowing the extent of how dangerous cancer can be once detected - surely it’s better to be safe than sorry?

In order to prevent over-diagnosing, the scientists believe that countries such as Europe and North America, where mammography takes place, should reconsider the reasoning behind screenings. Switzerland has already taken action as a result of a previous Danish study and decided not to offer a national mammography programme. The scientists of the BMJ research wrote: “Our results support the views of some commentators that the rationale for screening by mammography should be urgently reassessed by policy makers”.

However, in a statement from the American College of Radiology and Society of Breast Imaging, the study was referred to as “incredibly misleading analysis”. Concerns have risen that the study will be used to create new guidelines around the screening process. But the ACR and SBI stressed that the results “should not be used to create breast cancer screening policy as this would place many women at increased risk of dying unnecessarily from breast cancer”.

Until they decide how to react to the findings, all we can do is be vigilant and aware - check yourself regularly and make an appointment as soon as you suspect anything isn’t quite right. That’s the best lifesaver we have.

For more information about breast cancer visit www.nhs.uk

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